Transport of viscous fluids along pipeline for delivery to a refinery or other storage facility presents a myriad of challenges. One major challenge is recovering and transporting high viscosity petroleum products from well sites to refineries or storage facilities. In many known petroleum-containing sites, very little petroleum may be obtained by known means because of the high viscosity of the petroleum products.
Various techniques are known for aiding in the recovery of viscous petroleum and facilitating its transport to a refinery, storage site, or other location. These techniques include, for example, mechanical pumping, mechanical pumping combined with steam injection, and mining. Pumping unit limitations have a negative impact on the economics of producing viscous oil found in many parts of the world from pumped wells. The high viscosity of these crude oils results in low pump volumetric efficiency and high flow rate pressure drop. When extracted from the well, the viscous oil must be transported from the field to a refinery or shipping terminals.
Heavy oils exhibit a viscosity generally from 10,000 to 500,000 cP at room temperature. As a result, according to current practice pumping and heating stations are used to maintain a low viscosity for transport along pipelines. However, prolonged pumping interruptions often occur resulting in cold crude oil with concomitant plugging of pipes and pumps. Insulating hundred of miles of pipe is usually cost prohibitive. Heating the crude oil likewise consumes a large amount of energy and is cost ineffective. Diluents (e.g., fuel oil or kerosene) are sometimes used to reduce viscosity for pumping and transport. However, the large amount of diluent required is not readily available in the production area and, furthermore, the diluent would have to be recovered at the pipe end and pumped back to the field over great distances.
There thus exists an ongoing need for improved methods to decrease the viscosity of hydrocarbons to improve pump performance and operating efficiency thereby enhancing production. There exists a specific need for enhancing recovery and transport of viscous and extremely viscous petroleum such as that found in heavy oil reservoirs and other deposits.